I was born in 1974. I don't know if I can pinpoint when I first became aware of the speech as it is so ubiquitous in my life – it's as if it's always been there. By the time I learned about it at school, it was already in my gut, but I have no memory of it being explained to me. Both the iconography and the imagery of the speech – the Lincoln Memorial, the podium – all of that was already in me by the time I got to school; it was just a part of my family life. The very first time I saw the memorial I thought of Martin Luther King and that speech and what that day meant. It was vandalised recently and I was horrified. It was defacing a hallowed space, but for me that was nothing to do with the president. For me, the Lincoln Memorial has less to do with Lincoln than it does to do with that speech; for me, it's about King and that day.

Dr King's life is of a greater significance than just the speech, though. The older I get, the more deeply I respect and appreciate his commitment to non-violence. I really believe it is the only sustaining principle of life. I've come to love him deeply from a place that is beyond the simplicity of civil rights history and that deeply informs my life. It's a reach for something higher. All of us can be prone to both physical and verbal violence. Even the violence of hatred. When I think of people who make me sick – the Dick Cheneys of the world – I try to remember him. Violence is soulless and empty and the only way we're going to survive is through non-violence.

We've come tremendously far since the speech, and I say that in the aftermath of the Trayvon Martin case. I followed every bit of that trial and when [George] Zimmerman was acquitted I was broken. I had to explain what was happening to my six-year-old because I was weeping and probably frightening her. She'd seen me obsessing over the trial, listening to it on my iPhone, and asked why it was so important. So I explained to her in terms of an ongoing conversation that we're having about race and people making assumptions about difference. I explained a man made an assumption on difference, and a boy lost his life. But you have to remember that in 1963 there were not universal voting rights, the Civil Rights Act of 1964 hadn't been passed. So the fact that I am walking unscathed though LA, in my inter-racial marriage, voting and eating where I want – which is most people's experience – there's no way the speech hasn't had a tremendous impact.

Does that mean we don't have a lot further to go? No, we do. I do take heart from the fact that when the verdict came down, the outrage and the protest did not have a universal colour. This wounded white people, Asian people, British people, Indian people. That speaks to me.

I spent time on a project with Taylor Branch, who is the prize-winning author of Parting the Waters:America in the King Years, and I've read all 3,000 pages! I feel so lucky that I've gotten to understand what lies behind the speech. The big refrain of "I have a dream" only came about because on the day, when he was talking, Mahalia Jackson, who was standing in the wings, said: "Tell them about your dream." The writer in me was blown away that some of that speech was so contemporaneous. It was so beautiful – a call and response that is so integral to black culture. I just love that, it gives me chills every time.

More recently, in terms of civil rights, the Supreme Court's vote to repeal a provision of the Voting Rights Act [a landmark civil rights-era electoral law designed to protect minority voters] is one of the paradoxes of progress. I think it was Ruth Bader Ginsburg who said throwing out federal pre-clearance [permission to change voting systems] was like throwing away your umbrella in the rain because you're not getting wet. The fact that it has worked leads people to think we don't need it any more. But it's a reminder that America is an ongoing experiment. It will be tested and tested and tested. We need to decide which side of the freedom experiment we wish to stand on.

I think what happened in the Supreme Court was a blow, but a reminder to be ever-vigilant, and that we need to get back in there and fix the situation. I think that's what [attorney general] Eric Holder is trying to do on a state-by-state level. I don't mean to diminish it – it is a blow – but a part of me feels that America's commitment to its freedom is a fluid and elastic thing. We'll never say: "We're done with it" – it's an ongoing battle.